Electric-motor control.



Patnted Mar. I3, |900. W. R. HAMLEN.

ELECTRIC MOTOR CONTROL.

(Application med Apr. 19, '15:99.)

M [INEI/TOR' (No Model.)

WIT/153359:. CT Z Qn.

'Uivrrnn STATES PATENT Carica.

WELLS R. HAMLEN, OF J OHNSTOWN, PENNSYLVANIA, ASSIGNOR TO TIIE JOHNSONCOMPANY, OF PENNSYLVANIA.

ELECTRIC-MOTOR CONTROL.

SPECIFICTON forming part of Letters Patent No. 645,088, dated March 13,1900.

Application filed April 19, 1899. Serial No. 713,691. (No model.)

To @ZZ whom, t may concer/t:

Be it known that I, WELLS R. HAMLEN, of Johnstown, in the county ofCambria and State of Pennsylvania, have invented a new and usefulImprovement in Electric-Motor Control, of which the following is a full,clear, and exact description, reference being had to the accompanyingdrawings, which form a part of this speciiication.

My invention relates to electric systems of control for operating aplurality of motors, and has for its general object the provision of animproved method for accelerating and regulating the speed of the motorsby means of certain changes successively effected in the relationsbetween the motors as a whole and between the individual elementsthereof.

lVhile the invention is especially designed for use in connection withrailway-motors,'it is also applicable to other uses.

Broadly considered, my invention consists in a method of accelerating aplurality of motors by which the motors are shifted from a seriesrelation of their elements to a multiple relation by intermediate stepsin which one element of each motoris connected in multiple with thecorresponding element of the other motor or motors, the other elementsbeing in series. These steps enable me to utilize the resistance andcounter electromotive force of the motors to advantage in changing themfrom series to multiple, at the same time enabling me to prevent thelarge wastage occurrin g when the methods ordinari ly in vogue are used,which methods use resistances in the multiple positions in the same wayand for the same purpose as in the ordinary startin g-rheostat employedwith a motor or motors in which the motor-circuit is a fixed one at alltimes. On the other hand, my novel method, as previously outlined and aswill hereinafter be described more in detail, does not require acomplicated system of connection or produce bad inductive effects uponthe motors.

My invention also consists, in connection with such changes, of othersteps and combinations thereof whereby abrupt changes in the resistanceof the motor-circuits and toorapid acceleration of the motors areavoided.

In connection with my invention I employ external resistance orresistances, together with means for utilizing the same in the wellknownrheostatic manner when starting the motors in series and also utilizingthese same resistances or portions thereof to weaken the iields of themotors by shunting part of the current around them.

My invention also consists in certain other novel features of regulationin connection with the method above generally described, as arehereinafter described, and pointed out inthe appended claims.

Referring to the accompanying drawings, Figure l is a diagram showingtwo electric motors, a controller, and such parts of the wiring andconnections as serve to illustrate the nature and mode of operation ofmy invention. Fig. 2 shows, diagraminatically,the successive circuitconnections or changes made by the operation of the controllingswitch.

Referring to Fig. l, the letters A A2designate the armatures of the twoelectric motors, and F F2 the respective iield-coils of said motors.Squares l to 13, inclusive, designate a series of fixed contact-brushes,which form part of the controlling-switch, the balance of which consistsof a plurality of moving contacts-such, for instance, as contact-piecesmounted on a cylinder or drum arranged to be rotated by anoperating-lever. This type of controlling-switch is old in the art in sofar as its general mechanical construction is concerned, and I haveshown only the electrical contacts and their connections. These contactsare represented by the rectangles la to 26" and are divided into fourdifferent groups, each of which is electrically disconnected from theothers, but whose individual contacts are each connected electrically toall the others of that group. Contacts 1a to 9, inclusive, comprise onegroup; contacts l0a to 13, a second group; contacts la@ to 2l,inclusive, a third group; contacts 22L to 26a, inclusive, a fourthgroup. Certain of the contacts, as 9, 14C, 15, 2l, and 22a, whilebelonging electrically to the groups in which they are above classified,in point of position with respect to brushes, are included on a portionof the controller drum or cylinder which belongs otherwise to anadjacent group, whereby cer- IOO ` and connections 2C.

tain of the brushes are designed to operate with contacts of twodifferent groups in different positions of the controller. Brushes 6, 7,and 11 are shown as being of this class.

The numerals 15 to 2i designate a series of brushes which constitute thefixed contact members of a reversing-switch which is also provided withgroups of movable contacts C. This switch and its connections form nopart of the present invention and are shown only for the purpose ofenabling the circuits to be traced. For this purpose it will besufficient to consider only the contacts C C2 O3 C4 C, with which itwill be assumed hereinafter that the brushes 15 to .24 are inengagement.

The brush No. 1 is connected to the highpotential or trolley side of thecircuit (indicated at T) through the usual portions of the car-Wiringand instruments. (Not shown.) Brush No. 2 is connected to brush No. 15through an external resistance R' and connection 2. Brushes 3 and 4 arealso connected to brush 15 through portions of said resistance Brush 5is also connected to brush 15 by connection 2C, brush 6 to brush 19 byconnection GC, brush 7 to brush 18 by connection 7C, brush S toconnection 2c by connection 8C and resistances B2 BJ, brush 9 to brush22 by connection 9C, brush 10 to brush 24C through armature A andconnections 10c, brush 11 to ground G2 through armature A2 andconnections 11C, and brush 12 to brush 23 by connection 12C. Brushes 16and 17 are connected to each other through field F and conductors 16Cand 17? and brush 2O to brush 21 through field F2 and conductors 2OC21C.

The dotted vertical lines 1 2, the., indicate the several positions ofthe brushes 1 to 13 on the movable contacts in passing from a series toa multiple connection of the motors, and Fig. 2 shows,diagrammatically,the connection of the two motors and their elements at eachposition of the said brushes 1 to 13. At the first position of thesebrushes brushes 3, 4E, 5, 8, and 13 are not engaging any of the movablecontacts; but brushes 1, 2, 6, 7, 9, 10, 11, and 12 are respectively inengagement With contacts in, 2, los, 12e, isa, 19, 22e, and 23a, and thecourse of the current (assuming brushes 15 to 241 to be engaging thecontacts C', C2, C3, C4, and C5) is as follows: from trolley T to brush1, contacts 1 2, brush 2, resistance R', connection 2C, brush 15,contact C, brush 16, connection 16C, field F, connection 17e, brush 17,Contact O2, brush 18, connection 7G, brush 7, contacts 1 2n 10a, brush6, connection GC, brush 19, contact C3, brush 20, connection 20C, fieldF2, connection 21, brush 2l., contact C4, brush 22, connection 9C, brush9, contacts 18 19a, brush 10, connection 10, armature A' to brush 24,contact C, brush 23, connection 12C, brush 12 to contacts 23m-22, brush11, connection 11C, through armature A2 to ground G2. In this positiontherefore the current passes through the artificial resistance R andthrough the field-magnets and armatures of both motors in series. Thisis shownlin position 1 of Fig. 2. At the next position the only changemade in the contacts is that brush 2 passes oft the contact 2 and brush3 becomes engaged with the contact L1f. The effect of this change, itwill be seen, is to cut out of the motor-circuit a portion of theartificial resistance BJ. made in the circuit. At the third positionbrush it engages Contact 6 and brush 3 has left contacts 4% The effectof this change is to cut out still more of the resistance R withoutdisturbing otherwise the circuit. In the fourth position brush 4 hasleft contact G and the brush 5 has engaged contact 7a. The current nowpasses directly from the contact 1n to contact 7, to brush 5, connection2C, duc., as in the previous positions, resistance R', however, beingentirely cut out. Up to this point it will be noted that nothing butordinary rheostatic regulation has been employed. In the fifth positionbrush 2 engages contact 3 and brush 8 engages contact 163. Otherwise thepoints of contact are the same as in position et. The effect of thesechanges is that the current divides, one part passing from brush 5,through connection 2C, and thence through both fields and armatures asbefore and the other part passing through the resistance R', connection3C, brush 8, contacts 16 and 19, to brush 10, and thence through botharmatures in series. In this position the resistance is no longer usedrheostatically, but is used as a shunt to the field-winding, so that thefields may be weakened and the counter electromotive forcecorrespondingly decreased, thereby allowing more current to pass to thearmatures and accelerate them. The next three positions are passover ortemporary positions, and it is not deemed nec- 'essary to trace out theconnection in detail. In the first of these positions,(position 6) theengagement vof the brush 7 with the contact 14 (while still bridgingonto the contact 12a) of the third group short-circuits the field F2,and by the contact of the brush 13 with contact 25a the armature A2isalso short-circuited. The next position (by reason ofthe passing ofbrush 7 from contact 12L wholly onto contact 1M) breaks the circuitthrough field F2 and (by reason of the disengagement of brush 11 withcontact 22) cuts out the armature A2. The eighth position by reason ofthe fact that the brush 7 again engages a contact of the second group(contact 13a) once more puts the two iields in series, armature A2remaining cutout. At the ninth position, which is an essential workingposition and perhaps the most important feature of the system, the twofields remain in series, but the two armatures are coupled up inparallel. The parallel coupling of the armatures results in aconsiderable acceleration of the speed; but this is sufficientlycounteracted by the series coupling ofthe two fields and theirconsequent maximum resistance and abnormal strength to give no more thanthe desired amount of acceleration. Thus thefirst posi- No other changesare` tion in which the armatures are in parallel they are protected fromreceiving too great a rush of current not only because of the ohmicresistance of the two fields in series, but also by the counterelectromotive force caused by the abnormally-strong fields. This changeis effected by reason of the brush 11 being in engagement with thecontact 2l of the fourth group, while brushes l2 and 13 remain inengagement with the contacts 23 and 25?. By reason of this change thecurrent is divided, part going by brush 10 and connection 10 to armatureA' and thence to ground and the other part going by brush 1l andconnection 11c through armature A2 to ground. In position 10, which isalso a working or notch position, brushes 3 and 3 have engaged,respectively, the contacts 5 and 17, of the first and third groups,respectively,thereby throwing part of resistance R' and resistance R2 inshunt to the fields F' F2, which remain in series with each other,armatures A' A2 also remaining in parallel with each other. The effectof this change is to again reduce the strength of the fields byproviding an additional path for the current. Positions 11, 12, and 13are temporary or passover positions. In position 11 the brushes 3 and 8have left the contacts 5 and 17, thereby cutting the resistances R' R2out of circuit. Brushes 12 and 13 have also left the contacts 23 25,thereby breaking the ground connection of the armature A'. In position12 the brush 10 has left the contact 19, cutting out armature A', thecurrent passing from contact 21 to brush 11 through armature A2 toground. In position 13 brush 5 has passed from the contact 7 of the rstgroup and brush 6 has left contact 1l of the second group and engagescontact 9 of the first group, thereby cutting out field F', the othercontacts remaining the same as in the last position. Position 14 is thelast position and brin gs'the two motors as a whole in parallel with thefields and armatures of each motor in series. This is effected asfollows: Brushes 1, 5, 6, 7, 9, 10, 11, 12, and 13 are respectivelyengaged with contacts 1, 8, 9, 15, 18, 20, 21, 24, and 261. The courseof the current is now from trolley T to contact 1 to contacts 8 9. Hereit divides, one part passing by the brush 5, connection 2, brush 15,contact C', b'ru'sh 16, connection 16, field F', connection 17, brush17, contact C2, brush 18, connection 7, brush 7, contact 15, and contact20 to brush l0, connection 10, through armature A', brush 24, contactC5, brush 23, connection 12, brush 12, contacts 2a 26, and brush 13 toground. The other part passes from contact 9 to brush 6, connection 6 tobrush 19, contact C3, brush 20, connection 20, connection 20, field F2,brush 21, contact C4, brush 22, connection 9, brush 9, contact 1S tocontact 2l, brush 1l, connection 1l through armature A2 to ground.

It will be observed therefore that in my method of control I start withthe two fields and the two armatures connected in series with each otherand with artificial resistance; that I gradually cut the resistance outof circuit while retaining the series connections of the motor elements;that I next use the same resistance in sh unt with the motor-fieldsstill in series; that I next pass rapidly through a series ofpreparatory changes in which first one field and one armature areshort-ci rcuited, then out out, and, thirdly, the fields are connectedin series with one armature to a Working position, wherein the twofields are connected in series with the two armatures in parallel; thatI next throw the resistance into parallel with the two fields in seriesand the two armatures in parallel; then by successive preparatorychanges, in which first one armature and then one field are cut out, Ibring the motors as a Whole to multiple relation. In this manner I amable with the waste of very little power in external resistances and bythe movement of a single operating-lever to attain a gradualacceleration of the motors and without making at any time such an abruptchange as to injure the motors.

The apparatus which I have herein shown and described for carrying intoeffect my iinproved method of control is claimed in a divisionalapplication filed by me. I do not wish, however, to be limited to thisparticular apparatus in the practice of my invention, nor do I Wish tobe limited toimmaterial and non-essential details involved in the methodas above described.

Having thus described my invention, what 1 claim as new, and desire tosecure by Letters Patent, is

1. The method of accelerating a plurality of electric motors, whichconsists in starting with the motor elements all in series with eachother and with external resistance, gradually reducing and finallycutting out the resistance while maintaining the series relation, thenconnecting one element of each motor in multiple with the correspondingelement of the other motor, and finally connecting the motors as a wholein parallel.

2. The method of accelerating aplurality of electric motors whichconsists in starting the motors with their elements all connected inseries, then cutting out one element of each motor, then connecting oneelement of each motor in multiple with the corresponding element of theother motor or motors, with the other elements in series, then againcutting out one element of each motor, and finally connecting the motorsas a whole in multiple.

3. The method of acceleratinga plurality of electric motors, whichconsists in starting the motors with their elements connected in series,then placing a shunt-resistance in parallel with their fields, thenconnecting the two armatures in multiple and removing said shunt, thenagain shunting said fields, and nally connecting said fields in parallelwith said shunt removed.

4. The method of shifting two motors from series to parallel relationwhich consists in IOO IIO

placing a shunt-resistance in parallel with their fields, thenconnecting one element of each motor in multiple With the correspondingelement of the other motor, and the other elements in series with eachother, and cutting out the resistance, then again shunting the fields,and finally removing the held-shunt and connecting the two motors inparallel, substantially as speciiied.

5. The method of accelerating tWo electric motors, which consists instarting them With their elements all connected in series with eachother and with an artificial resistance, then rheostaticallyaccelerating them by gradually cutting out said resistance andsubsequently connecting said resistance in shunt with the fields, thenshort-circuiting one field and one armature, then connecting the fieldsin series and the armatures in parallel, then again introducingresistance in shunt With the fields, next successively cutting out theresistance, the armature of one motor and the field of the other, andnally connecting the motors as a whole in parallel.

G. The method of operating a pair of electric motors which consists instarting With the two fields and the tWo armatures in series, thenconnecting one pair only of said elements in multiple, and finallyconnecting the motors as a Whole in multiple and preparatory to each ofsaid changes, introducing resistance in parallel circuit with theseriesconnected elements of the motors.

7. The method of accelerating a pair of electric motors, which consistsin first gradually reducing the resistance of the motor-circuit as thecounter electromotive force increases, then bringing the motors to arelation Wherein one element of each motor is'in series With thecorresponding element of the other motor, and the other elements are inmultiple to each other, subsequently weakening the fields of the motors,and finally connecting the motors in parallel.

In testimony whereof Ihave affixed my sigi nature in presence of twoWitnesses.

WELLS R. HAMLEN.

1Witnesses:

EDWARD SCHULTZ, M-YRoN E. OGDEN.

